Y. Ghorbani Amir, A. Zolriasatein, H. Torabian,
Volume 6, Issue 2 (12-2020)
Abstract
The aim of this study is to investigate the effect of rotary frictional welding process variables on microstructure, mechanical and physical properties of copper-aluminum dual-tube pipes. For this purpose, using a thermosetting friction welding machine, a copper pipe (99.44% purity) with a similar diameter aluminum tube (1050), was welded in three different conditions with different friction pressures and forging, and then by metallographic, hardening and microstructural testing it placed. The results of this study showed that with increasing friction pressure from 10 and 15 Bar respectively, in the interconnected phase, fuzzy interclass metal samples were created and caused a great loss in the deformation percentage and tensile strength of the interconnected sample. Also, with the reduction of frictional pressure and the removal of forging pressures down to 5 Bar, there is no proper bond between the two samples and formed in the interface between porosity and cracking. The most suitable result for the microstructure, mechanical and physical properties of the samples is in tubes with an outside diameter of 15 mm and an inner diameter of 10 mm, for samples having a friction pressure of about 10 Bar and a forge pressure of 15 Bar. The presence of intermetallic Al-Cu phases such as CuAl2, due to higher electrical resistance and ceramic nature, increases the electrical resistance of the joint and, on the other hand, the presence of cracks and pores has reduced the flow rate and eventually increased electrical resistance of the samples
M. Safari, H. Deilami Azodi ,
Volume 6, Issue 2 (12-2020)
Abstract
In this paper, the experimental investigation of formability of friction stir welded ultra-thin sheets of IF steel is investigated experimentally. First, the sheets are joined by friction stir welding process based on the tests determined according to the Taguchi design of experiments. The investigated parameters in the welding process are as tool rotational and traverse speeds. Then, the tailor welded blanks are formed based on dome height test up to the defect stage and the dome height is measured for each test. Therefore, the effects of friction stir welding process parameters on formability of friction stir welded ultra-thin sheets of IF steel are evaluated. The results show that by increasing the rotational speed, the dome height in forming process decreases, while with increasing the traverse speed, the formability of tailor welded blanks by friction stir welding process improves. Also, the results of optimization based on signal to noise ratio method show that the tool rotational speed has the greatest effect on the dome height of tailor welded blank.
